T-N-T is short for "Tap and Torque" a unit I did in class that covered how to use a tap and die set as well as how to properly identify and torque different styles and types of screws and bolts. For our final project we had to identify three kinds of bolts including their thread pitch, length, and width, and then drill holes into a piece of aluminum and use a tap tool to put threads into the aluminum.
These three pictures show me using the tap to put threads into the holes I drilled into the aluminum to the specifications of the bolts I was assigned. The picture below is the three bolts successfully threaded into the aluminum block.